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LiverTox: Clinical and Research Information on Drug-Induced Liver Injury [Internet]. Bethesda (MD): National Institute of Diabetes and Digestive and Kidney Diseases; 2012-.

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LiverTox: Clinical and Research Information on Drug-Induced Liver Injury [Internet].

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Red Yeast Rice

Last Update: June 4, 2018.



Red yeast rice is bright reddish-purple fermented rice which is used as a dietary supplement, predominantly as a cholesterol lowering agent. The reddish-purple color derives from the mold Monascus purpureus. Red yeast rice use has been associated with very rare instances of acute, clinically apparent liver injury.


Red yeast rice is a traditional Chinese medicine used as an aid to digestion and revitalizing agent. More recently, red yeast rice was shown to have a cholesterol lowering effect and was marketed as a natural means of treating hyperlipidemia. However, chemical characterization of the components of red yeast rice (monascus purpureus) demonstrated the presence of several monacolins, one of which (monacolin K) is chemically identical to lovastatin, a commercially available HMG-coenzyme A inhibitor widely used in the management of hyperlipidemia. While concentrations of lovastatin in commercial preparations of red yeast rice extract are variable, some have pharmacologically active concentrations of lovastatin. Controlled trials have shown that red yeast rice extract can lower total serum and LDL cholesterol. However, these same preparations have also been linked to rare cases of myopathy and liver injury similar to what occurs with lovastatin. Red yeast rice extracts are available over-the-counter in multiple formulations and with variable concentrations of monacolins. The FDA has ruled that red yeast rice extracts that have more than trace amounts of monacolin K (lovastatin) cannot be sold as a dietary supplement, but some products with detectable levels of lovastatin are commercially available. The other components of red yeast rice may have independent effects of lipid levels.


In prospective controlled trials, red yeast rice extract formulations have not been associated with serum enzyme elevations or clinically apparent liver injury. However, there have been isolated case reports of liver injury in patients on red yeast rice extracts. A proportion of patients with liver injury attributed to red yeast rice extract were reported to have similar episodes of serum enzyme elevations during conventional lovastatin therapy.

Likelihood score: C (probable rare cause of clinically apparent liver injury).

Mechanism of Injury

Both the liver injury and myopathies attributed to red yeast rice extracts are probably due to the presence of lovastatin in concentrations of 1 to 10 mg per tablet. Lovastatin is metabolized in the liver via CYP 3A4 and its liver injury is likely due to a toxic or immunogenic metabolite.

Outcome and Management

The reported cases of liver injury attributed to red yeast rice have been mild-to-moderate in severity and self-limited in course. There have been no cases of acute liver failure or vanishing bile duct syndrome attributed to red yeast rice. Persons with liver injury attributed to red yeast rice extracts should avoid exposure to lovastatin, but switching to other statins may be safe, although it should be done with caution.

Drug Class: Herbal and Dietary Supplements

See also: Lovastatin


Case 1. Acute hepatitis due to red yeast rice.

[Case from: Navarro VJ, Barnhart H, Bonkovsky HL, Davern T, Fontana RJ, Grant L, Reddy KR, et al. Liver injury from herbals and dietary supplements in the U.S. Drug-Induced Liver Injury Network. Hepatology 2014; 60:1399-408. PubMed Citation]

A 67 year old woman with hypercholesterolemia developed abnormal liver tests 7 weeks after starting red yeast rice. She had a history of abnormal liver tests in the past, but routine testing before starting red yeast rice revealed minimal elevations of ALT levels (47 U/L), but normal values for AST, alkaline phosphatase and bilirubin. She did not drink alcohol, had no risk factors for viral hepatitis and no history of drug allergies. Her past medical history included hypertension, aortic valve replacement, hysterectomy, hypothyroidism, osteoporosis and previous urinary tract infections. Her other medications included valsartan, hydrochlorothiazide, low dose aspirin, thyroid extract, multivitamins, calcium, magnesium, zinc and Metamucil, all of which she had taken for more than a year. Laboratory testing initially showed an ALT of 479 U/L, AST 330 U/L, alkaline phosphatase 228 U/L and total bilirubin 0.7. She felt well and had no new symptoms. The red yeast rice was continued and she was followed as an outpatient. Over the next two weeks, however, her liver tests worsened and the red yeast rice was stopped. She subsequently developed fatigue, nausea, dark urine and jaundice (Table). Tests for acute hepatitis A, B, C and E were negative as were routine autoantibodies. Serum albumin ws 4.0 g/dL and globulins 2.3 g/dL. An abdominal ultrasound and CT scan were normal with normal liver size and texture and no evidence of biliary obstruction or masses. She underwent a liver biopsy that showed acute hepatocellular injury without fibrosis, consistent with either a drug induced liver injury or autoimmune hepatitis. She was monitored on no therapy and gradually improved. When seen one year after stopping the botanical product, she was asymptomatic and all liver tests were normal.

Key Points

Medication:Red yeast rice
Pattern:Hepatocellular (R ratio=6.8)
Severity:2+ (jaundice, not hospitalized)
Latency:7 weeks
Recovery:Approximately 4 months
Other medications:Valsartan, hydrochlorothiazide, aspirin, thyroid extract

Laboratory Values

Time After
Time After
Alk P
7 weeks-74792280.7
8 weeks2 days8643561.0INR 1.0
9 days11014130.6Liver biopsy
12 weeks37 days11852906.3
14 weeks48 days9702944.2
15 weeks55 days8611693.5INR 1.0
16 weeks62 days6201502.7
17 weeks69 days6431613.1
18 weeks76 days5821463.2
19 weeks83 days4821434.1
4 months90 days4511543.7INR 1.0
1 year1 year201060.8
Normal Values <45 <125 <1.2


This patient developed an acute hepatitis arising about 2 months after starting red yeast rice for hypercholesterolemia. The hepatitis was mild-to-moderate in severity, but was prolonged which raised the question of autoimmune hepatitis. Against this diagnsosis was the absence of autoantibodies and normal serum globulin levels. She did not receive corticosteroids and ultimately the liver injury resolved. This case was reviewed by an expert causality committee and was judged to be "highly likely" drug induced liver injury from red yeast rice.



Red Yeast Rice – Generic


Herbal and Dietary Supplements


Fact Sheet at National Center for Complementary and Integrative Health, NIH


Red Yeast Rice
Monacolin K
R400000000UnspecifiedNot Applicable


References updated: 04 June 2018

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    (62 year old woman developed fever, nausea and fatigue 4 months after starting red yeast rice extract [ALT 211 U/L, bilirubin and Alk P not given], resolving within several months of stopping).
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    (Analysis of two large US surveillance systems for adverse events reported between 2004 and 2017 found 1459 reports mentioning red yeast rice, only 1% of which were designated a hepatobiliary related; no details provided).


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